1. Field of the Invention
The present invention relates to a contact-state obtaining apparatus that obtains a contact state in which a tire contacts a road surface, and a tire-deformation detecting apparatus that detects a deformation of a tire.
2. Related Art Statement
Japanese Patent Application Publication 6-341822A discloses, as an example of a contact-state obtaining device, a side slip angle obtaining device including a first velocity detecting portion that is provided on the side of a body of a vehicle and detects a first velocity at which a contact point of a tire with a road surface moves on a straight axis line about which the tire is rotated; a second velocity detecting portion that detects a second velocity at which the contact point of the tire moves on a straight centerline of the tire; and a side slip angle calculating portion that calculates a side slip angle of the tire based on the first and second velocities.
The side slip angle obtaining device obtains, as the side slip angle, an angle relative to the centerline of the tire, of a displacement-direction vector representing a direction in which the tire displaces, i.e., a composite vector obtained by addition of a vector obtained by translating a velocity of a gravity center of the vehicle's body from the gravity center to the contact point of the tire and a tangential vector on the contact point about a vertical axis (i.e., a yaw axis) passing through the gravity center. The first velocity detecting portion detects, as a first component of the displacement-direction vector, the first velocity at which the contact point of the tire moves on the straight axis line about which the tire is rotated, the second velocity detecting portion detects, as a second component of the displacement-direction vector, the second velocity at which the contact point of the tire moves on the straight centerline of the tire, and the side slip angle calculating portion calculates the side slip angle of the tire based on the first and second velocities.